Properties of the Number 19985

Nineteen Thousand Nine Hundred Eighty-Five

Basics

Value: 19984 → 19985 → 19986

Parity: odd

Prime: No

Previous Prime: 19979

Next Prime: 19991

Digit Sum: 32

Digital Root: 5

Palindrome: No

Factorization: 5 × 7 × 571

Divisors: 1, 5, 7, 35, 571, 2855, 3997, 19985

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100111000010001

Octal: 47021

Duodecimal: B695

Hexadecimal: 4e11

Square: 399400225

Square Root: 141.36831328130077

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Numbers k such that 2^k + 11 is prime. A102633

Triangle read by rows: T(n,k), n >=1, 0 <= k <= C(n,k), = number of n X n symmetric positive definite matrices with 2's on the main diagonal and 1's and 0's elsewhere and with k 1's above the diagonal. A80858

Number of k <= P(n) such that rad(k) | P(n), where rad(n) = A007947(n) and P(n) = A002110(n). A363061

Numbers k such that 2·k+1, 3·k+2, 4·k+3 and 5·k+4 are primes. A138700

Number of partitions of n into 6 or more distinct parts. A347573

Numbers that match polynomials over {0,1} that have a factor containing -3 as a coefficient; see Comments. A208182

Number of compositions (ordered partitions) of n into distinct parts where no part is a multiple of 4. A332310

a(n) = ∑_{1 <= x₁ <= x₂ <= x₃ <= x₄ <= n} gcd(x₁, x₂, x₃ , x₄, n). A343518

Numerator of Bernoulli(n, -3/4). A157860

Number of numbers <= n whose set of prime factors is a subset of the set of prime factors of n. A10846